Recuperative burners use heat in furnace flue gases to preheat air, e.g., by having the flue gas and air flow past a common partition, to reduce fuel requirements, and eductors are generally used to pull the flue gases through the heat exchanging passages. In a "self-recuperative burner" the heat exchanger is made integral with the burner to avoid the heat loss and usage of space associated with having the heat exchanger located externally of the furnace. Recuperative burners generally operate at higher flame temperatures, owing to the preheated air, thereby increasing the NO.sub.x content in the furnaces and the flue gases.